The present invention relates to a device for regulating the power output of an electrical generator in motor vehicles.
A device of this type is known, for example, from German patent document DE 101 06 944 A1. In the known generator regulator units having temperature limiting for thermal protection, the limiting temperatures are permanently and unchangeably programmed in the regulator units. Therefore, a special limiting temperature tailored to the individual application must be provided in the regulator units for every application in the vehicle. A high variant manifold thus arises when constructing generators having integrated regulator units.
It is an object of the present invention to improve a device of the type cited above in regard to standardization and thus cost optimization.
This and other objects and advantages are achieved according to the present invention by a device for regulating the power output of an electrical generator in motor vehicles having an internal combustion engine, in which the generator has a regulator unit, which prevents exceeding at least one limiting temperature by regulation. The regulator unit is connected via a bidirectional interface to an electronic control unit assigned to the internal combustion engine. The control unit and the regulator unit are designed in such a way that the regulator unit, after transmitting at least one value relevant to the limiting temperature from the control unit to the regulator unit, stores the particular applicable limiting temperature determined by this value.
A value relevant to the limiting temperature may, for example, be the particular applicable limiting temperature itself, an offset value which is added by the regulator unit to a base value to reach the particular applicable limiting temperature, or a parameter by which the regulator unit selects the particular applicable limiting temperature from a parameter-related list of limiting temperatures. The parameter may be an application-specific data relating to the cooling conditions of the generator and/or an operation-specific data relating to the heat generation in the generator environment, or may be calculated therefrom.
The control unit may determine the value relevant to the limiting temperature as a function of at least one application-specific data relating to the cooling conditions of the generator, such as the engine installation space, as a fixed value.
Alternatively or additionally, the control unit may determine the value relevant to the limiting temperature variably as a function of at least one operationally-specific data relating to the heat generation in the generator surroundings, such as the instantaneous engine speed or the instantaneous engine output.
The present invention is based on the following findings:
The regulator unit may be programmed with the same base value as the limiting temperature for every application in the vehicle. According to the present invention, this base value may be overwritten using a particular new applicable limiting temperature or have a new offset value applied to it, resulting in a new applicable limiting temperature, when the unit is first put into operation in the vehicle, at least for the application-specific adaptation. The base value may also be used as an emergency operation limiting temperature in case of interface error. According to the present invention, different limiting temperatures may be determined for various components. The temperature limiting may occur according to the prior art.
Through the present invention, it is possible to provide standards which may be designed as correspondingly flexible by the interface communication. Through these standards, it is possible to achieve significantly simpler component handling in the replacement part market. Unnecessary trimming of the generator output power or no limiting at temperatures which are too high is often to be observed due to the limiting at a single fixed limiting temperature according to the prior art.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.